I have a 1st gen Nexus 7 (32GB). I used the steps at https://wiki.ubuntu.com/Nexus7/Installation to successfully install Ubuntu 13.04 desktop onto the tablet. It was working fine and then I decided to upgrade to Ubuntu Touch. I booted the tablet into fast boot mode but the commands 'adb devices' and 'sudo fastboot devices' would not see the device. I am performing these steps from an Ubuntu 12.04 desktop PC. Prior to installing 13.04 the device was seen fine. I made the mistake of performing the 'Device factory reset' step from https://wiki.ubuntu.com/Touch/Install - Step 2. Now when I try to boot the device I get the following:

mount: mounting /dev on /root/dev failed: no such file or directory
mount: mounting /dev on /root/sys failed: no such file or directory
mount: mounting /proc on /root/proc failed: no such file or directory
Targe filesystem doesn't have requested /sbin/init.
No init found. Try passing init= bootarg.

BusyBox v1.20.2 (Ubuntu 1:1.20.0-0ubuntu1) built-in shell (ash)
Enter help for a list of built-in commands.

(initramfs)

I have searched the web but every reference to this problem is from people who still have ADB access to the device so they can recover by flashing the tablet again. I can attach a keyboard to the USB port and access the BusyBox console but I don't know what steps to do to recover from my error. Any suggestions would be helpful. Thanks